A redistricting panel has demolished California’s exquisitely gerrymandered congressional map, ushering in the prospect of a massive turnover in the state’s delegation and imperiling the careers of some of Capitol Hill’s most powerful pols.

The Citizens Redistricting Commission, a bipartisan 14-member group composed largely of political neophytes, unveiled the first draft of the state’s congressional blueprint Friday, ending an era of unparalleled stability for a 53-member delegation that has seen remarkably little turnover over the last decade.

The plan marks a dramatic transformation in the state’s congressional landscape, and will create electoral troubles for members of both parties. GOP Rep. Gary Miller, a veteran congressmen from Orange County, is drawn into a Democratic-leaning district; while 67-year-old Republican Rep. Elton Gallegly finds himself in the same seat as Armed Services Committee Chairman Buck McKeon. Both appear to have limited political options.

Prominent lawmakers did not escape unscathed. GOP Rep. David Dreier, who chairs the House Rules Committee, is drawn into a Democratic-leaning seat. Democratic Rep. Howard Berman, the former chair of the House Foreign Services Committee, is drawn into the same district as fellow Democratic Rep. Brad Sherman, who has more than $3 million in the bank.

In some cases, members who have skated to easy reelection bids for years will find themselves in newly competitive districts. GOP Rep. Dan Lungren, a nine-term congressman who is facing a rematch against Democratic physician Ami Bera, is placed in an only mildly Republican-leaning seat in the Sacramento area. Democratic Rep. Lois Capps, facing a challenge from former GOP Lt. Gov. Abel Maldonado, now finds herself in an only slightly Democratic-leaning district.

The draft appears to boost Democrats overall, with strategists from both sides estimating that the party could pick up a handful of seats statewide. With line-drawers unraveling a decade-long gerrymander, the new map places several southern California-area Republicans in tenuous political positions while apparently establishing safe seats for every Bay Area Democrat.

“I would say there [will be] fewer Republicans in California if the map were to hold,” said Matt Rexroad, a Republican consultant in the state, adding that Democrats could gain as many as a half-dozen seats.

“The demographics of California benefits Democrats, and in politics demographics are destiny,” said Ross, who noted that Democrats currently control every statewide office.

The commission, proposed by former GOP Gov. Arnold Schwarzenegger in 2009 and approved by voters in a ballot measure last year, designed the map with an eye toward ending the incumbent protection-oriented mindset that defined previous rounds off redistricting in the state. One of the biggest advantages to the new process, the commission wrote in a Thursday press release, is that “Districts are drawn without regard to political incumbents and partisan considerations.”

In unveiling the map on Friday, commission leaders said they expected some alterations to be made before the final version of the map is released in mid-August. The commission, which has been meeting since this spring, will solicit public input over the next two months before releasing the final draft.

In some cases, the new map provides incentive for veterans to retire. Dreier and Gallegly, both of whom had meager first fundraising quarters this year, will now need to reassess their political options.

The new commission is one of several changes that will have a dramatic impact on the state’s congressional delegation. Last year, voters approved a ballot measure that implemented a “jungle primary” system. Under the system, the top two vote-getters in a primary regardless of party affiliation advance – meaning that lawmakers in strongly liberal or conservative districts could face difficult primary and general election races.

CORRECTION: An earlier version of this article had an incorrect spelling of Ami Bera’s name.

CORRECTION: An earlier version of this article listed Elton Gallegly's age at 77. He is 67.